Electronic assembly with emi shielding heat sink

ABSTRACT

An example electronic assembly includes a substrate that has a first surface and a second surface. The first surface of the substrate includes a grounding ring. The electronic assembly further includes one or more electronic components that are mounted on the first surface of the substrate such that the grounding ring at least partially surrounds the electronic components(s). A heat sink engages the electronic component(s) and the grounding ring in order provide cooling and EMI shielding to the electronic components(s). In some embodiments, the grounding ring surrounds the entire electronic components(s) and the heat sink engages the entire grounding ring, although in other embodiments, the grounding ring may partially surround the electronic components(s) and/or the heat sink may engage just a portion of the grounding ring.

FEDERALLY SPONSORED RESEARCH OF DEVELOPMENT

The U.S. Government has a paid-up license in this invention and theright in limited circumstances to require the patent owner to licenseothers on reasonable terms as provided for by the terms of Contact No.MDA904-02-3-0052, awarded by the Maryland Procurement Office.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is related to an electronic assembly, and moreparticularly to an electronic assembly that includes a heat sink whichprovides electromagnetic interference (hereafter EMI) shielding.

2. Background Information

Electronic devices generate heat during operation. Thermal managementrefers to the ability to keep temperature-sensitive elements in anelectronic device within a prescribed operating temperature.

Historically, electronic devices have been cooled by natural convection.The cases or packaging of the devices included strategically locatedopenings (e.g., slots) that allowed warm air to escape and cooler air tobe drawn in.

The advent of high performance electronic devices now requires moreinnovative thermal management. Each increase in processing speed andpower generally carries a “cost” of increased heat generation such thatnatural convection is no longer sufficient to provide proper thermalmanagement. If the heat generated by such electronic devices is notremoved at a sufficient rate, the devices may overheat resulting indamage to the devices and/or a reduction in operating performance of thedevices.

One common method of cooling an electronic device includes thermallycoupling a heat sink to an electronic device. A typical heat sinkincludes protrusions (e.g., fins or pins) which project from a body ofthe heat sink. The protrusions give the heat sink a larger surface areasuch that the heat sink dissipates a greater amount of thermal energyfrom the electronic device into the surrounding environment. Heat sinksare fabricated from materials with high thermal conductivity in order toefficiently transfer thermal energy from the electronic device to theambient environment.

A fan is often used in conjunction with the heat sink to improve theheat sink's rate of cooling. The fan causes air to move past the fins onthe heat sink. Moving air past the heat sink increases the rate ofconvection between the heat sink and the ambient environment where theheat sink is located. Increasing the rate of convection between the heatsink and the ambient environment reduces the temperature of the heatsink, thereby enhancing the heat sink's ability to transfer heat fromthe electronic device.

The ability to thermally manage electronic devices becomes even moredifficult when multiple electronic components are mounted in closeproximity to one another within an electronic system. As an example,multiple chipsets, dies, processors, memory modules and/or applicationspecific integrated circuits (hereafter asics) may be mounted in closeproximity to one another such that the heat generated by each electroniccomponent can adversely effect the performance that particular componentas well as the other electronic components.

Electronic devices also generate EMI during operation with highperformance electronic components generally producing relatively largeamounts of EMI. The EMI that is generated by such electronic componentsmay be large enough to reduce the operating performance of theelectronic components which are included in an electronic system.

The heat sinks in existing electronic assemblies are typically used tocool high performance electronic components when multiple electroniccomponents are mounted in close proximity to one another within anelectronic device. Therefore, what is needed is an electronic assemblywhich includes a heat sink that provides high performance cooling andEMI shielding to an electronic component when electronic components aremounted in close proximity to one another within an electronic system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an exploded perspective view of an example electronicassembly.

FIG. 2 illustrates a schematic surface view of the electronic assemblyshown in FIG. 1.

FIG. 3 illustrates an exploded perspective view of another exampleelectronic assembly.

FIG. 4 illustrates a schematic surface view of the electronic assemblyshown in FIG. 3.

FIG. 5 illustrates an exploded perspective view of another exampleelectronic assembly.

FIG. 6 illustrates a schematic surface view of the electronic assemblyshown in FIG. 5.

FIG. 7 is a plan view of the opposing surface of the substrate shown inFIG. 5.

FIG. 8 is a perspective view of the electronic assembly shown in FIG. 5where the electronic assembly further includes a printed circuit boardand a connector that connects the printed circuit board to thesubstrate.

DETAILED DESCRIPTION OF THE INVENTION

In the following detailed description of the preferred embodiments,reference is made to the accompanying drawings which form a part hereof,and in which is shown by way of illustration specific embodiments inwhich the invention may be practiced. It is to be understood that otherembodiments may be utilized and structural changes may be made withoutdeparting from the scope of the present invention.

FIGS. 1-2 illustrate an example electronic assembly 10 of the presentinvention. The electronic assembly 10 includes a substrate 12 that has afirst surface 14 and a second surface 16. The first surface 14 of thesubstrate 12 includes a grounding ring 18.

The electronic assembly 10 further includes an electronic component 20that is mounted on the first surface 14 of the substrate 12 such thatthe grounding ring 18 at least partially surrounds the electroniccomponent 20. As shown most clearly in FIG. 2, a heat sink 30 engagesthe electronic component 20 and the grounding ring 18 in order providecooling and EMI shielding to the electronic component 20.

In the example embodiment that is illustrated in FIGS. 1 and 2, thegrounding ring 18 surrounds the entire electronic component 20 and theheat sink 30 engages the entire grounding ring 18, although in someembodiments the grounding ring 18 may partially surround the electroniccomponent 20 and the heat sink 30 may engage just a portion of thegrounding ring 18. It should be noted that the grounding ring 18 may beplaced on the first surface 14 of the substrate as part of themanufacturing process that is associated with the substrate 12, or addedjust before the heat sink 30 is attached to the grounding ring 18.

The electronic assembly 10 may further include fasteners 40 that extendthrough the heat sink 30 and the substrate 12 in order to secure theheat sink 30 to the substrate 12. It should be noted that any number andtype of fasteners 40 may be used to secure the heat sink 30 to thesubstrate 12. In other embodiments, the heat sink 30 may be secured tothe substrate 12 in some manner besurfaces using fasteners (e.g., byusing an adhesive).

Although FIG. 2 shows that the heat sink 30 and the substrate 12 mayfully enclose the first electronic component 20, it should be noted thatin some embodiments the heat sink 30 and the substrate 12 may onlypartially enclose the first electronic component 20. The determinationas to whether the heat sink 30 and the substrate 12 fully or partiallyenclose the electronic component 20 will depend in part on the (i)degree of shielding that is required for the electronic component 20;(ii) size of electronic component 20; (iii) arrangement of theelectronic component 20 on the substrate 12; (iv) degree to which thegrounding ring 18 surrounds the electronic component; and/or (v)manufacturing consurfacerations associated with electronic assembly 10.

It should be noted that the heat sink 30 may be a unitary structure orformed from more than one structure that is joined together to form heatsink 30. As an example, the fins 34 may be one or more sectional insertsthat extend through opening(s) in the base 32 and are attached to thebase 32.

The electronic assembly 10 may further include additional electroniccomponents 22A-H that are mounted on the first surface 14 of thesubstrate. In the example embodiment that is illustrated in FIGS. 3 and4, the grounding ring 18 entirely (or partially) surrounds some of theelectronic components 20, 22A-D on the first surface 14 of the substrate12 while in the example embodiment that is illustrated in FIGS. 5 and 6,the grounding ring 18 entirely (or partially) surrounds all of theelectronic components 20, 22A-H on the first surface 14 of the substrate12. The heat sink 30 is adapted to engage each of the electroniccomponents that are at least partially surrounded by the grounding ring18.

Although FIGS. 3-6 shows that the heat sink 30 and the substrate 12 mayfully enclose each of the electronic components that are surrounded bythe grounding ring 18, it should be noted that in some embodiments theheat sink 30 and the substrate 12 may only partially enclose each of theelectronic components that are surrounded by the grounding ring 18. Asdiscussed above, the determination as to whether the heat sink 30 andthe substrate 12 fully or partially enclose some the electroniccomponents will depend in part on the (i) degree of shielding that isrequired for the electronic component 20; (ii) size of electroniccomponent 20; (iii) arrangement of the electronic component 20 on thesubstrate 12; (iv) degree to which the grounding ring 18 surrounds theelectronic component; and/or (v) manufacturing consurfacerationsassociated with electronic assembly 10.

In some embodiments, the electronic component 20 may be an applicationspecific integrated circuit while one or more of the other electroniccomponents 22A-H may be memory devices. In the example embodiments thatare illustrated in FIGS. 3-6, four memory devices 22A-D are on one sideof the application specific integrated circuit 20 and four more memorydevices 22E-H are on an opposing side of the application specificintegrated circuit 20.

In some embodiments, the electronic assembly 10 may further include oneor more additional electronic components 24 that are mounted on thesecond surface 16 of the substrate 12. FIG. 7 is a plan view of theopposing surface of the substrate shown in FIG. 5 which illustrates anexample embodiment where additional memory devices 24 are mounted on thesecond surface 16 of the substrate 12. The particular number andarrangement of electronic components on the substrate 12 will depend inpart on the desired operation and function of the electronic assembly 10within an electronic device.

FIG. 8 illustrates an example embodiment of the electronic assembly 10where the electronic assembly 10 further includes a printed circuitboard 50 and a connector 52 that connects the printed circuit board 50to the substrate 12. In the illustrated example embodiment, thesubstrate 12 includes a lateral edge 54 such that the connector 52engages the lateral edge 54 of the substrate 12. It should be noted thatalthough the substrate 12 is shown as being orthogonal to the printedcircuit board 50, the substrate 12 may be at other angles relative tothe printed circuit board 50.

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat any arrangement which is calculated to achieve the same purpose maybe substituted for the specific embodiment shown. This application isintended to cover any adaptations or variations of the presentinvention. Therefore, it is intended that this invention be limited onlyby the claims and the equivalents thereof.

1. An electronic assembly comprising: a substrate that includes a firstsurface and a second surface, the first surface of the substrateincluding a grounding ring; an electronic component mounted on the firstsurface of the substrate such that the grounding ring at least partiallysurrounds the electronic component; a heat sink that engages theelectronic component and the grounding ring in order provide cooling andEMI shielding to the electronic component; a printed circuit board; anda connector that connects the printed circuit board to the substrate,wherein the substrate is orthogonal to the printed circuit board and thesubstrate includes a lateral edge such that the connector engages thelateral edge of the substrate.
 2. The electronic assembly of claim 1,wherein the grounding ring surrounds the entire electronic component. 3.The electronic assembly of claim 1, wherein the heat sink engages theentire grounding ring.
 4. The electronic assembly of claim 1, whereinthe heat sink is mounted directly to the substrate.
 5. The electronicassembly of claim 1, wherein the heat sink is mounted directly to thegrounding ring.
 6. The electronic assembly of claim 1, furthercomprising fasteners that extend through the heat sink and the substratein order to secure the heat sink to the substrate.
 7. The electronicassembly of claim 1, wherein the heat sink and the substrate enclose theelectronic component.
 8. The electronic assembly of claim 1, furthercomprising additional electronic components mounted on the first surfaceof the substrate, and wherein the grounding ring at least partiallysurrounds a plurality of the electronic components on the first surfaceof the substrate and the heat sink engages each of the electroniccomponents in the plurality of the electronic components.
 9. Theelectronic assembly of claim 8, wherein the grounding ring entirelysurrounds all of the electronic components in the plurality of theelectronic components on the first surface of the substrate.
 10. Theelectronic assembly of claim 9, wherein the heat sink engages the entiregrounding ring.
 11. The electronic assembly of claim 8, wherein the heatsink and the substrate enclose all of the electronic components in theplurality of the electronic components on the first surface of thesubstrate.
 12. The electronic assembly of claim 8, wherein one ofelectronic components is an application specific integrated circuit andanother of the electronic components is a memory device.
 13. Theelectronic assembly of claim 12, wherein some of the other electroniccomponents are memory devices.
 14. The electronic assembly of claim 13,wherein at least two memory devices are on one side of the applicationspecific integrated circuit and at least two more memory devices are onan opposing side of the application specific integrated circuit. 15-17.(canceled)
 18. The electronic assembly of claim 1, further comprising atleast one additional electronic component mounted on the second surfaceof the substrate.
 19. The electronic assembly of claim 18, wherein atleast some of the additional electronic components that are mounted onthe second surface of the substrate are memory devices.